An organic EL light-emitting device is a device equipped with an organic electroluminescence element obtained, for example, by successively superposing a translucent substrate, such as a glass or a plastic, an anode constituted of a transparent electrode, an organic functional layer constituted of an organic thin film, and a cathode. Such organic EL light-emitting devices suitable for practical use are being developed enthusiastically in recent years for the reasons, for example, that these light-emitting devices emit light areally at high luminance with a voltage as low as several volts and that it is possible to make the devices emit light in any desired color tone by selecting luminescent substances.
It is known that when an organic EL light-emitting device is allowed to stand, with the organic functional layer and the cathode being exposed to the air, the device undergoes a phenomenon (shrinking) in which the non-luminescent region expands due to atmospheric moisture as if the luminescent region of the organic functional layer shrinks, resulting in a deterioration of the organic electroluminescence element. Consequently, a sealing structure for blocking moisture is necessary. A hollow seal obtained by bonding a glass or metallic sealing can 17 for moisture blocking to the back of an organic electroluminescence element by means of an adhesive 15 to form a hollow structure and disposing a desiccant 16 within the sealing can 17, as shown in, for example, FIG. 6, has hence been proposed.
In the case of this hollow seal, however, since the deterioration is prevented by causing the desiccant to absorb the moisture which has permeated from outside the seal, an expensive member which is made of a glass, metal, etc. and in which a recessed portion for placing the desiccant therein has been formed in the center is necessary as a sealing base. In addition, because of the space inside the seal, the heat generated by the luminescence is less apt to be dissipated and there is a fear that the life of the organic electroluminescence element may be shortened. Furthermore, a prolonged tact time is necessary for applying the resin used for bonding the periphery of the sealing base. In the case of using a glass frit, an expensive apparatus such as a laser is necessary.
Under these circumstances, techniques of solid sealing have been proposed in which a layer of an adhesive is directly formed on an electrode and a flat glass plate or metal foil, as a sealing base, is fixed through the adhesive, for the purposes of a cost reduction, improvement in heat dissipation property, and reductions in thickness and weight. Examples thereof include a solid seal obtained by disposing a dehydrating agent including an alkaline earth metal, e.g., Ca, around the luminescent region of an organic electroluminescence element, sealing the surfaces thereof with an epoxy resin, and fixing a glass plate disposed thereon (patent document 1) and a solid seal obtained by sealing an area including and larger than the cathode of an organic electroluminescence element with an ultraviolet-curable resin which contains a crystalline zeolite and bonding a sealing substrate to the surface thereof (patent document 2).